首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1031789篇
  免费   73583篇
  国内免费   1960篇
耳鼻咽喉   13958篇
儿科学   27647篇
妇产科学   25596篇
基础医学   147444篇
口腔科学   32036篇
临床医学   89769篇
内科学   205904篇
皮肤病学   21839篇
神经病学   82108篇
特种医学   39157篇
外国民族医学   80篇
外科学   161104篇
综合类   18407篇
现状与发展   1篇
一般理论   282篇
预防医学   71945篇
眼科学   22943篇
药学   79643篇
  3篇
中国医学   2565篇
肿瘤学   64901篇
  2021年   9103篇
  2019年   8863篇
  2018年   12281篇
  2017年   9542篇
  2016年   10719篇
  2015年   12131篇
  2014年   16286篇
  2013年   23113篇
  2012年   32562篇
  2011年   33872篇
  2010年   19634篇
  2009年   18321篇
  2008年   31630篇
  2007年   32743篇
  2006年   32941篇
  2005年   31426篇
  2004年   29970篇
  2003年   28435篇
  2002年   27488篇
  2001年   55226篇
  2000年   56881篇
  1999年   47505篇
  1998年   11477篇
  1997年   10085篇
  1996年   10117篇
  1995年   9347篇
  1994年   8681篇
  1993年   7927篇
  1992年   35761篇
  1991年   34093篇
  1990年   32920篇
  1989年   32037篇
  1988年   29156篇
  1987年   28384篇
  1986年   26438篇
  1985年   25251篇
  1984年   17958篇
  1983年   15260篇
  1982年   7943篇
  1979年   15848篇
  1978年   10672篇
  1977年   9117篇
  1976年   7928篇
  1975年   8672篇
  1974年   10514篇
  1973年   9886篇
  1972年   9382篇
  1971年   8870篇
  1970年   8445篇
  1969年   7941篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
Trotter's syndrome is a clinical triad of unilateral deafness, neuralgia affecting branches of the trigeminal nerve, and defective mobility of the soft palate, which is caused by malignant tumors involving the lateral pharyngeal recess (Rosenmüller's fossa). It is an ominous presentation, which can masquerade as dental or masticatory pain. Computerized tomography (CT) can be used not only to explain the anatomic basis of Trotter's syndrome but also to determine the extent and distribution of the malignant tumor involved. The advantages of CT over conventional radiography are illustrated by a case of adenoid cystic carcinoma that presented as Trotter's syndrome. Perineural invasion by tumor is shown on the gross level for the first time with CT, and important diagnostic considerations, which may aid in the early diagnosis of future cases, are discussed.  相似文献   
992.
Acinar zone 3 areas in liver biopsy specimens from 23 alcoholics and 47 non-alcoholics were investigated by light microscopy and transmission electron microscopy to asses fibrosis in the perisinusoidal space and to evaluate the role of the lipocytes. Quantitative analysis by light microscopy on toluidine blue-stained sections showed a significant reduction in number of lipocytes--median values of 2.7 and 1.2 lipocytes per 100 hepatocytes in biopsies from chronic alcoholics showing no or varying degrees of zone 3 fibrosis, respectively, as compared to 3.6 lipocytes per 100 hepatocytes in non-alcoholic livers. By transmission electron microscopy, the reduction in number of lipocytes was related to a corresponding increase in number of cells rich in rough endoplasmic reticulum and microfilaments (activated lipocytes). The occurrence of activated cells was significantly correlated to fibrosis of the perisinusoidal space. Activation of lipocytes and collagenization of the perisinusoidal space appeared before light microscopic evidence of fibrosis and were topographically not related to Mallory bodies or alcoholic hepatitis.  相似文献   
993.
The late results--up to six years--after axillo-femoral bypass reconstruction are reported for 85 patients with leg ischaemia who were regarded as poor-risk patients for aortic bypass surgery, or who had aortic graft infection. Velour-Dacron grafts and expanded polytetrafluoroethylene (PTFE, Gore-Tex)--grafts have been used. The cumulative patency rate (life table) six years after graft implantation was 64% (PTFE-grafts) and 58% (Velour-Dacron grafts). The corresponding cumulative limb salvage rate six years after graft implantation was 88% when PTFE grafts were used and 77% when Velour-Dacron grafts were used. Our results demonstrate that axillo-femoral reconstruction is a useful procedure with a good patency rate 6 years after implantation. This procedure should be considered when dealing with poor risk patients with severe leg ischaemia.  相似文献   
994.
995.
We introduced a mouse IL-2 cDNA expression vector into an IL-2-dependent mouse helper T cell line HT-2. Transfected cells secreted substantial amounts of IL-2, to which they themselves responded by proliferating without further requirement for exogenous IL-2. The proliferation was a direct function of the cell density and was inhibitable by antibodies against IL-2 or IL-2-R, indicating the autocrine nature of the proliferation. Those producing higher amounts of IL-2 were found to be tumorigenic when inoculated into nude mice. The latency period of tumor development correlated inversely with the level of IL-2 secreted. Tumor cells proliferated in vitro in an IL-2 autocrine fashion indistinguishable from that of the inoculated cells. We thus provide evidence that the aberrant activation of the IL-2 autocrine circuit can lead T cells to malignant transformation.  相似文献   
996.
Direct (intraarterial) and two indirect (using a mercury sphygmomanometer [MS] and an automatic [auscultatory] device) methods of blood pressure measurement were compared in intensive care patients (N = 32). One trained observer blind to both automatic and direct measurements obtained all indirect MS measurements. All direct and indirect measurements were made on the same arm. Direct measurements were obtained from 10-second strip chart recordings. In normotensive patients both indirect measurements of systolic blood pressure (SBP) underestimated the direct SBP; however, only the SBP value obtained with the automatic device (106 mm Hg) was significantly different, p less than .05, from the direct SBP value (120 mm Hg). No significant difference was noted between methods in measurement of normotensive diastolic blood pressure. In hypertensive patients direct SBP was significantly greater, p less than .05, from both values obtained by indirect measurement. In patients without hypotension the automatic device may be substituted for the MS and direct blood pressure methods. The automatic device may offer the advantage of decreasing observer bias and variability in blood pressure measurement.  相似文献   
997.
Spinal Ewing's sarcomas are rare and cause problems in differential diagnosis. The radiologic, nuclear medicine and CT findings in two children with histologically proven Ewing's sarcoma are presented and problems in differential diagnosis discussed. Biopsy should be done early.  相似文献   
998.
999.
1000.
Neurotropin (NSP) is an extract isolated from the skin of rabbits inoculated with vaccinia virus. The present study examines the possible action of NSP on the number and function of immunocompe tent cells in mice. The experiment showed that NSP had no effect on both T and B lymphocytes of nor- malimmunized mouse spleen. The degree of plaque forming cell reaction and titre of specific antibody showed no significant differences when the NSP treated group and controls were compared. How- ever, NSP exhibited promotive effect on specific antigen binding cells in the early stage of immune responses. It was also noted that the rosette forming capacity of human T lymphocytes in vitro was restor- ed markedly by NSP. These results suggest that NSP possesses certain immunostimulating activity, particularly on the specific antigen binding cells and human T lymphocytes.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号